Decolorizing organic substances



Jan. 3l, 1950 AP. LIEN ErAL DEcoLoRIzING ORGANIC suBsTANcEs 2 Sheets-Sheet 1 Filed Feb. 28, 1947 Jan. 3l, 1950 A. P. LIEN Erm.

DEcoLoRIzING ORGANIC suBsTANcEs 2 Sheets-Sheet 2 Filed Feb. 28,. 1947 Patented Jan. 31, 1950 DECOLORIZING ORGANIC SUBSTANCEB Arthur P. Lien, Hammond, Ind., Bernard L. Evering, Chicago, lll., and Bernard H. Shoemaker. Hammond, Ind., assignors to Standard Oil gmpany, Chicago. Ill., a corporation o! In- Application February 28, 1847, Serial No. 731,4

14 Claims. (Cl. 19614.25)

This invention relates to the decolorization of organic substances, particularly hydrocarbons or mixtures of hydrocarbons. More particularly, the invention relates to the decolorization of hydrocarbon oils, particularly' petroleum oils and petroleum oil fractions and hydrocarbon waxes.

'I'his invention finds application in many industries. For example, in the manufacture of hydrocarbon oils such as petroleum oils, particularly viscous petroleum oils such as lubricating oils, it is highly desirable that the color bodies or color-forming bodies be removed from suchprod ucts in order to obtain a finished product which is of good color and substantially free oi' color bodies which are largely responsible for the formation of sludge and/or varnish during use or storage. Furthermore, in the treatment of petroleum oils it is frequently the practice to extract such products with a solvent, such as for example phenol, furfural, nitrobenzene, Chlorex (beta, beta dichloroethyl ether), etc. to remove therefrom aromatics and/or naphthenes which are responsible in a large measure for the dark color of such materials. The extracts resulting from such solvent extractionprocesses can be used as plasticizers and for other purposes; however, because of their very dark color,I` such extracts are not extensively used. Other organic substances which are frequently improved by decolorization are natural fats and fatty oils, such as animal, vegetable and marine fats and oils, such as tung oil, linseed oil, rapeseed oil, iish oil, tallow, etc., as well as terpenes, such as rosin. ester waxes, such as Sperm oil, etc.

It is an object of the present invention to provide an improved method of decolorizing organic substances, such as hydrocarbon oils and waxes, natural fats and fatty oils, ester waxes, rosln, etc. Another object of the present invention is to provide a method of decolorizing hydrocarbonI oils and hydrocarbon oil fractions. Still another object of the present invention is to provide an improved method of decolorizin'g viscous hydrocarbon oils. A further object of the invention is to provide a method of improving the color of extracts resulting from the solvent extraction of hydrocarbon oils, such as petroleum oils.

Other objects and advantages of the present invention will become apparent from the following description thereof read in conjunction with the accompanying drawings which form a. part of the specication and in which Figure 1 is a flow diagram of carrying out the invention, and Figure 2 is a flow diagram of a modified method of carrying out the invention.

In accordance with the present invention, or.

2 ganic materials, such as for example hydrocarbons or mixtures oi' hydrocarbons, for example hydrocarbon oils such as petroleum oils and petroleum oil fractions, natural fats and oils, and rosin are 'eiiectively decolorized by extracting such materials with a solvent comprising essentially a complex of boron fluoride with an oxygen-ated organic compound or halogen, preferably chlorine, derivatives of such oxygenated organic compounds, said solvent being employed in conjunction with a diluent, preferably one having a relatively low boiling point, for example fromv about F'.`to about 300 F., and substantially free o! aromatic hydrocarbons. Preferably, the diluent ls an aliphatic hydrocarbon having from about 3 to about 7 carbon atoms in the molecule, such as propane, butane, pentane, hexane or heptane although other hydrocarbons heavier than heptane can be used.

While the complexes of boron iluoride with aliphatic or aromatic oxygenated` compounds can be used, we prefer to employ complexes of boron fluoride -with an oxygenated alkane compound selected from the class consisting of ethers, esters and acids. having not more than about 5 and preferably not more than 3 carbon atoms in the alkyl group, and the halogen, preferably chlorine, derivatives thereof.

Specific examples of organic oxyeenated compounds which can be employed for forming the boron iluoride complexes are the following:

Methyl ether Methyl formate Ethyl ether Ethyl formate Propyl ether Butyl formate Butyl ether Ethyl propionate Amyl ether Acetic acid Phenol Formic acid Methyl ethyl ether Propionic acid Methyl acetate Anisol Ethyl acetate Pyran Propyl acetate Tri tetra and penta- Amyl acetate methylene oxides and the halogenated, preferably chlorinated, de-` rivatives of the above, as for example B,B' dichloroethyl ether y(Chlorex), chloroacetic acid, etc.

While complexes of boron fluoride with Oxygenated organic compounds as a class are en'ective solvents for eiecting la separation oi' color bodies from hydrocarbonmixtures, they are all not equal in their eiectiveness and may vary with different complexes, with the composition of the mixture being extracted and with the conditions 01 extraction, as will be described hereinafter.

The boron iuorlde .complexes are readily prepared by bubbling a slight molar excess oi boron fluoride through the oxygenated compound, e. g.,-

ether, ester, acid, etc., and then subjecting to reduced pressure to remove the excess boron fluoride. In some cases, itis desirable to carry out 1 the BF; stripping step at lower than'room temto give a partial pressure of from` aboutv one pound or less to about 150 pounds per square inch in vconjunction with the herein described complexes in order to effect improved extraction. Our invvention also 'contemplates the use of small amounts of HF in conjunction with the boron nuoride complexes.

The choice of any particular organic oxygenated compounds used in forming theboron fiuo- 25 a settler I9 wherein any carryover complex is ride complex will depend upon the feed to be treated, with due consideration being given to the boiling point of the complex inA relation to the boiling range of the feed materialand the extract to be obtained therefrom. Fo'r example, the boron fluoride-methyl ether 'or vboron fluorideethyl ether complexes boil at relatively low temperatures, namely 258 to 262 F. Therefore, if the extracted material boils in this temperature range, it is preferable to use, as will be described hereinafter, a complex which is recovered by dissociation into BF; and organic compound, in which case the'organic compound should have a boiling point higher than the extracted material. In most cases complexes having a boiling point lower than that ofthe extracted material will 4 be used, in which' case the complex can be recovered by distilling or flashing of! the same from the extract. Y

.The diluent referred to above plays an important role in the present invention. to insure more eilicient contact between the boron fluoride complex and the material being extracted, and also acts as a'counter-solvent for keeping the aromatics, ifv present, in the raffinate, thus l ti se ration of the 50 making for a more se ec ve pa drawn therefrom through line 21 and introduced color bodies Awith less change in thearomaticity of the raffinate. The diluent can be used in amounts varying from about 50 to about 500 volume percent, based on the feed stock, and preferably greater than 100 volume percent, and more specifically from about 100 to about 200 volume percent.

The extraction can be carried out over a wide temperature range of about 50 F. to about 150 F., or higher and preferably from about 40 F. to about 100 F. under anhydrous conditions. The quantity of complex used should be sufficient to Agive a diphasic separation, and depending upon the material being extracted can vary from about 10 volume percent to about 200 volume percent or more, based on hydrocarbon feed, exclusive of the diluent, and preferably from about 50 volume per cent to about 100 volume percent, although in some cases as little as -about 5 volume percent or less will give a satisfactory diphasic separation. `A -pressure'sufcient to keep lthe materials in a liquid phase should be maintained in the extractor. v l

The following `procedure of decolorizing a colored lubricating oil stock with a boron fluoride- It acts L5 .o lines 30, 32 and Il.

4 ethyl ether complex is given by way of illustration only and is not intended to be a limitation g of our invention. Referring to Figure l, a dark colored stock, e. g. the extract obtained from 5 extraction of a lubricating oil with conventional solvents, together with about 200 volume percent of a diluent, such as pentane, from storage tank I and through line Il, are introduced via line I2 into the bottom portion of an extractor I3,

l0 and countercurrently contacted with a boron l ing intimate contact can be employed. The boron fluoride-ethyl ether complex introduced into the extractor Il via line I4 is suitably obtained from a forming zone identified in the drawing as the complex mixer I5. Boron fluoride and ethyl ether for forming the complex and/or for makeup are introduced into the complex mixer I5 vla lines I6 and I'I, respectively.-

The railinate is removed overhead from the extractor I3 through a line Il and introduced into settled out and returned to the extractor I 3 through line 20. The raffinate free of carryover complex is withdrawn from the settler I9 through line 2| and introduced into the bottom portion of a fractionator 22 -provided with suitable heating means such as a heating coil 2l. In the fractionator 22, the diluent,. pentane, is recovered as an overhead and returned to the diluent storage tank I0 through line 24, while the boron fluorideethylether complex is recovered as a side cut and suitably passed to the complex mixer I5 via line 25. The decolorized raffinate, substantially free of diluent and boron fluoride complex is withdrawn from the fractionator 22through line 26. 0 It is to be understood, of course, that if the feed stockto be decolorized distils below the boiling point of the' complex, the decolorized ramnate, will of course, be recovered from the f-ractionator as a suitable side cut and the complex withdrawn from the fractionator asa bottom.' Likewise, if the diluent distils at a temperature above the distillation temperature of the feed stock, the decolorized rafllnate may berecovered as overhead and the diluent as a side cut.

The extract from the extractor I3 is withinto still 28 equipped with suitable heating means such as a heating coil 29. v Stili 28 may, if desired, be operated at reduced pressure. The contents of still 2l are maintained at a temperature sufficient to remove therefrom the boron uorideethyl ether complex as an overhead, which is either sent to the complex mixer I 5 via lines 30 and 3l or recycled to the extractor I3 via The extract, substantially free of complex, is withdrawn from the still 2B through line 33. It is to be understood, of course, that depending upon the relative boiling points of the extract and the boron fluoride complex,

under certain conditions the complex may be withdrawn from the still 2l as a bottom fraction and the extract as an overhead fraction or a side cut. n

The foregoing example illustrates a method of carrying out the herein described invention under certain conditions in'which the boron fluoride complex dissociates but is notdecomposed by distillation. However, certain boron fluoride complexes are decomposed into boron fluoride and the oxygenated organic compound when subananas 8 Jected to distillation, even under reduced pressure. When employing such complexes they cannot be recovered as in the hereinbefore described method. The following example illustrates one method of carrying out the invention employing a boron fluoride complex which is decomposable under distillation conditions. For the purpose of illustration, the following procedure provides a method of carrying out the invention employing a boron iluoride-Chlorex (beta, beta dichloroethyl ether) complex, hereinafter referred to as a boron iluoide-Chlorex complex.

Referring to Figure 2, the feed to be decolorized. for example a lubricating oil extract stock, together with about 200 volume percent of a diluent, such as pentane from diluent storage tank H and line HI are introduced via line ||2 into the extractor H3 and countercurrently .contacted with a boron fluoride-Chlorex complex introduced into the upper portion of the extractor ||3 from a complex forming zone, identified in the drawing as the complex mixer ||'5 via line ||4. Boron fluoride and Chlorex for forming the complex or as make-up can be introduced into the complex mixer 5 throughflines H0 and Il'l, respectively.

The railinate from the extractor ||3 is removed overhead through line I8 to a settler ||9 wherein any entrained boron fluoride-Chlorex complex is settled out and recycled to the extractor H3 through lines |20 and |2| or may be passed through line and |22 to a complex recovery unit as hereinafter described. The rafiinate from the settler ||9 is passed through line |23 to a fractionator |24 provided with a suitable heating means such as a heating coil |25. In the fractionator |24 any carryover boron iluoride-Chlorex'complex is decomposed and the boron fluoride removed overhead through line |26, and recycled to the complex mixer ||5 or to the boron fluoride supply source (not shown) via line IIS. The diluent in this case, pentane, is recovered from the fractionator |24 as a side cut and recycled to the diluent 'storage tank I|0 .via lines |21 and |28. The bottoms from the fractionator |24 comprising raiinate and Chlorex are withdrawn through line |29 and introduced into the fractionator |30 provided-with suitable heating means |3|. Chlorex is recovered 'from the fractionator |30 as a side cut fraction and withdrawn therefrom via line |32 and passed either to the complex mixer I5 or to the Chlorex supply source (not shown) via line ||'l. Any diluent carried over from the fractionator |24'is withdrawn from the fractionator |30 as an overhead via line |33 and recycled to the diluent storage tank ||0 through line |28. Raffinate substantially free of the complex and diluent is withdrawn from the fractionator |30 through the line |34. Obviously, in the event the product being-decolorized has a lower boiling point than the Chlorex, the decolorized product will be taken overhead from the fractionator |30 and the Chlorex will be withdrawn from the fractionator |30 as a bottom and passed to the complex mixer H5 or to the Chlorex supply source.

The extract from the extractor H3 comprising boron iluoride-Chlorex complex and the extracted material from the feed stock is removed from the extractor |I3 through line |35 and introduced into a fractionator |36 provided with suitable heating means such as heating coil |31 for maintaining a bottom temperature of about 180'F. to about 400 F. in the fractionator.

Boron nuoride-Chlorex complex from the-settler ||l maybe introduced into the fractionator |33 via lines |20, |22 and |35.l Boron iluoride- Chlorex complex is decomposed in the fractionator |30 kand the boron iluoride taken overhead through line |38 and passed either to the boron iluoride supply source (not shown) or to the complex mixer ||5 via line H0. Bottoms from the fractionator |36 are withdrawn through line |39 and introduced into fractionator |40 provided with suitable heating means such as heating coil |4|. Fractionator |40 is operated under conditions to eiect a separation of Chlorex and extract, the former usually being removed therefrom as an overhead through line |42, and passed either to the complex mixer Il 5 or to the Chlorex supply source (not shown) via line |I'|. The extract substantially free of the complex is removed from the fractionator |40 through line |43. It will be understood, of course, that the Chlorex may be withdrawn as a bottom product from the fractionator |40 and the extract as an overhead if the boiling range of the extract is below the boiling range of the Chlorex.

The boron iiuoride Chlorex mixer is operated under conditions to prevent excessive temperature due to the heat of reaction between the boron fluoride and the Chlorex.

While we have shown the separation of boron fluoride and Chlorex in separate fractionators, it is obvious that the decomposition and separation of boron iluoride and Chlorex can be accomplished in a single tower, if desired.

While we have described a continuous boron fluoride-Chlorex extraction process, the stock to be treated may be mixed with the Chlorex in a batchwise process and the boron iiuoride bubbled through the homogeneous solution to the point of providing one mole BF; per mole of Chlorex or to the point oi' saturation. The resulting mixture can then be settled to give a rafllnate phase and a lower BFE.` complex-extract phase.

The effectiveness of the herein described boron iluoride complexes in decolorlzing organic materials is demonstrated by the extraction of an East Texas gas oil cycle stock with various boron fluoride complexes at about 75 F., using one volume of the complex to each volume of oil. The results obtained are tabulated in Table I together with the results obtained with veral well known solvents for comparison.

` TABLE I Extraction of East Texas gas oil cycle stock ,y

Color Refractive Run No. Solvent NPA Index (DDN) l (control) 8 l. 5407 BF: 8- l. 5332 EF1-Methyl Ether complex. 7+ l. 5280 BFll-Mehlyl Ether complex+ 5 l. 533i uen 5 BFg-Ethyl Ether complex 2 1.4682 BFrChlorex complex 2 l. 4883 BFr-.Atic Acid Comp1ex 4. 5 1.6%)1 BFa-Ethyl Acetate complex-.. 6+ 1. 5191 BFr-Propyl Acetate complex 4. 5 l. 6028 BFg-a-picoline complex 0+ l. 4W BFS-Anisole complex 3 l. 4913 BFi-Propyl Ether oomplex 3. 5 l. 4837 13 Methanol i.. 8 l. 5372 14 Nltromethane 8 1.5262 l5 nillne 7 1.4913

l Fontane-#2 volumes C/volume oil. I Four successive dumps of fresh solvent.

The above data show the improvement in color resulting from the extraction of cycle stock with boron iluoride complexes of the present inventton. Run 4 illustrates the advantage o! using a diluent with the complex. Using adiluent resulted in a color improvement of about 2 units with less removal of aromatics, as shown by the higher refractive index. Runs 13-15 show that less effective color improvement is obtained with known solvents.

The decolorizing emciency of the herein described complexes is further demonstrated by the data in Table Il. These data were obtained by extracting various lubricating oil extracts at about '15 F. with the complex in the presence of pentane as the hydrocarbon diluent. The lubricating oil extracts were those obtained by extracting lubricating oil stocks for SAE 20 and 40 oils with Chlorex (beta, beta dichloroethyl ether) or with HF.

8 terial comprising extracting an organic material containing color bodies with a solvent consisting essentially of a complex of boron fluoride with an oxygenated alkane compound having not more than about carbon atoms in the alkyl group.

TABLE II Decolorization of lubricating oil extracts Run No. oi Volume NPA No. Fecd solvent Dumps Diluent Color ND" l.. SAE 2) Chlorex ExtractA 8 l. 564 2., do Blix-Methyl Ether Complex l 2 41/5-5 1. 5600 3 d0 .-do 2 2 41,5 1,5583 4.. do 4 2 41A 1.5583 5... t BFg-Ethyl Ether Complex. i 2 4 l. 5570 6.. ...do 2 2 Iii-3% 1.5545 1 A....do 4 2 1%-2 1.5470 8.. BFg-Ethyl Ether Complcx-i-BFii..." 1 2 2 l. 5512 a BFi-Chlorex Com lex 1 2 3 1.5457 l0 BFg-Ethyl Ether omplex 4 6 24% l. 5339 BFg-Ethyl Ether Complex. 4 6 7 1.5870 )8 1.579

BFJ-Ethyl Ether Complex l 2 4% 1. 5665 do 4 l0 3% 1.5665

Color when 3 cc. of thc extract is diluted with i7 cc. kerosene. iExcess BF; gas bubbled through a mixture.

iExtract from extraction of SAE iExtract from heating SAE lubricst1ng The addition of excess BF: is particularly effective as demonstrated by comparing Run No. 'I with Run No. 8, wherein approximately equivalent results were obtained with one dump operation instead of four dump as required in Run No. 7.

The high aromaticity of the final railinate from the HF extract feed stock (Run 11) is also noteworthy. This raiilnate gave superior plasticizing properties in poylvinyl chloride.

As demonstrated by the above data the present invention is effective in improving the color of petroleum oil solvent extracts, particularly lubricating oil solvent extracts. These extracts of improved color iind utility as plasticizers for resins, particularly synthetic resins such as vinyl chloride resins. The extracts from the extraction of petroleum oil stocks with anhydrous HF, particularly those involving a high temperature HF pre-treat (Run 11) are especially adapted as plasticizers because they are very highly aromatic in character.

By the term hydrocarbon oil" as used herein and in the appended claims, we mean to include the solvent extracts of such oils.

The term viscous hydrocarbon oil as used herein and in the appended claims means a hydrocarbon oil having a Saybolt Universal viscosity at 100 F. above 50 seconds.

While we have described our invention by reference to various representative compounds and have illustrated the invention by means of preferred embodiments thereof, the invention is not to be limited thereto, but includes within its scope such modifications and variations as come within the spirit of the appended claims.

We claim: y l. The method of decolorizing an organic ma- 20 lubricating oil stock with anhydrous HF at room temperature.

oil stock with HF at 330 F., followed by HF extraction at room temperature.

than about 5 carbon atoms in the alkyl group, and a small amount of free boron fluoride, said extracting being carried out in the presence of an aliphatic hyrocarbon diluent, said complex being employed in amounts suicent to give a dlphasic separation of a rafllniate phase comprising essentially a substantially decolorized organic material and an extract phase comprising essentially said complex and the color bodies extracted from said organic material.

3. The method of claim 2 in which an amount of free boron fluoride sufiicient to give a partial pressure of from about 1 pound to about 150 pounds per square inch is used in conjunction with the boron fluoride complex.

4. The method of decolorizing a hydrocarbon oil comprising contacting an hydrocarbon oil containing color bodies with a solvent consisting essentially of a complex of boron fluoride with an oxygenated alkane compound having not more than about 5 carbon atoms in the alkyl group in the presence of an aliphatic hydrocarbon diluent, said complex being employed in amounts sufficient to give a diphasic separation of a railinatc phase comprising essentially a substantially decolorized hydrocarbon oil, and an extract phase comprising essentially said complex and the color bodies extracted from said hydrocarbon oil.

5. The method of claim 4 in which the oxygenated alkane compound is an alkane acid.

6. The method of decolorizing a hydrocarbon oil comprising contacting an hydrocarbon oil containing color bodies with a solvent consisting essentially of a complex of boron fluoride with an alkane ester having not more than about 5 carbon atoms in the allwl group in the presence of an aliphatic hydrocarbon diluent said complex being employed in amounts sufficient to give a dicomprising contacting a petroleum oil containing color bodies with a solvent consisting essentially of a complex of boron fluoride with an alkane ether having not more than about carbon atoms in the alkyl group in the presence of an aliphatic hydrocarbon diluent boiling within the range of from about 90 F. to about 300 F., said complex 4being employed in amounts suflicient to give a diphasic separation of a raiIinite phase comprising essentially o1' a substantially decolorized petroleum oil and an extract phase comprising essentially said complex and the color bodies extracted from said petroleum oil.

10. The method of claim 9 in which the alkane ether is an ethyl ether. v

11. The method of claim 10 in which the ethyl ether is beta beta dichloroethyl ether.

12. The method of decolorizing a viscous hydrocarbon oil comprising contacting a hydrocarbon oil containing color bodies with a solvent consisting essentially of a complex of boron Iluoride with an oxygenated alkane compound having not more than about 5 carbon atoms in the alkyl group in the presence of an aliphatic hydrocarbon diluent boiling within the range of from about 90 F. to about 300 F., said complex being employed in amounts sumcient to give a diphasic separation of a ramnate phase and an extract phase. separating said ralnate phase comprising essentially a substantially decolorized hydrocar- 10 bon oil, a small amount oi' said complex and diluent and said extract phase comprising essentially said complex and the color bodies extracted from said hydrocarbon oil, and removing said complex and diluent from said ramnate and extract phases.

13. The method of claim 12 in which said diluent is employed in amounts of' at least 50 volume percent based on said hydrocarbon oil.

14. 'I'he method of decolorizing a hydrocarbon lubricating oil solvent extract comprising contacting a hydrocarbon lubricating oil solvent extract containing color bodies with a solvent consisting Vessentially of a complex of boron iluoride with an oxygenated alkane compound having not more than about 5 carbon atoms in the alkyl group in the presence of at least volume percent based on said extract of an aliphatic hydrocarbon diluent boiling within the range of from about F. to about 300 F., said complex being employed in amounts suillcient to give a diphasic separation of a raffinate phase and an extract phase, separating said raffinate phase comprising essentially a substantially decolorized hydrocarbon lubricating oil solvent extract, a small amount of said complex and diluent, and said extract phase comprising essentially said complex and the color 4bodies extracted from said hydrocarbon lubricating oil solvent extract and removing said complex and Vdiluent from said raffinate and extract phases.

ARTHUR P. LIEN.

BERNARD L. EVERING.

BERNARD H. SHOEMAKER.

REFERENCES CITED The following references are of record in the 111e of this patent:

UNITED STATES PATENTS Number Name Date 2,246,257 Kohn June 17. 1941 2,415,171 Horeczy Feb. 4, 1947 

1. THE METHOD OF DECOLORIZING AN ORGANIC MATERIAL COMPRISING EXTRACTING AN ORGANIC MATERIAL CONTAINING COLOR BODIES WITH A SOLVENT CONSISTING ESSENTIALLY OF A COMPLEX OF BORON FLUORIDE WITH AN OXYGENATED ALKANE COMPOUND HAVING NOT MORE THAN ABOUT 5 CARBON ATOMS IN THE ALKYL GROUP, IN THE PRESENCE OF AN ALIPHATIC HYDROCARBON DILUENT, SAID COMPLEX BEING USED IN AMOUNTS SUFFICIENT TO GIVE A DIPHASIC SEPARATION OF A RAFFINATE COMPRISING ESSENTIALLY A SUBSTANTIALLY DECOLORIZED ORGANIC MATERIAL, AND AN EXTRACT PHASE COMPRISING ESSENTIALLY SAID COMPLEX AND THE COLOR BODIES EXTRACTED FROM SAID ORGANIC MATERIAL. 